Rewrite:
1. The water bill was enormous because there was a crack in the water pipes.
-> Because of .................................
2. I love classical music because it makes me happy.
-> Classical music ..........................
3. When did you begin study English?
-> How long ...................................
4. She said to Long, "Please open the door!"
-> She told.....................
5. We cannot live without water.
-> If there .................
6. Let's play some games of tennis.
-> I suggest.........................
7. I told you about a person. He is at the door.
-> The person...........................